The major objective of the study is to analyze the process and mechanisms of professional socialization among residents in a new specialty, Emergency Medicine, and to compare their professional socialization with that of residents in two traditional specialities, Surgery and Internal Medicine. The concept of professional socialization refers to the process by which individuals, through their training, learn how to acquire the values and behavior of their professional group. In addition to the learning of professional skills, professional socialization involves: identifying with the profession through role models and reference groups; learning to deal with uncertainities and mistakes; developing realistic expectations of the profession in response to internal and external events during training; and developing commitment to the profession. The lack of previous comparative research in the area of professional socialization of medical residents and the current debate about the development of a speciality in Emergency Medicine led to the decision to systematically study the variations within and between residents of both newly developing and traditional specialized medical training programs. To study professional socialization, a panel study design was chosen. The following groups are in the panel: (1) those who complete a residency program or three years of residency training; (2) a follow-up of these residents after the first year of their post-residency acvitity; (3) those residents who drop out of the panel. In Group 1, hypotheses regarding professional socialization will be tested, including expectations, commitment, acquisition of professional skills, and attaining medical judgment. In Group 2, hypotheses regarding job satisfaction, commitment and career lines will be tested. Group 3 residents will be compared with Group 1 residents along these same dimensions.